1. Field of the Invention
The present invention relates to a rotary connector that electrically connects between a steering wheel and a body of an automobile, and more particularly to a rotary connector that incorporates a slip-ring mechanism.
2. Description of the Related Art
A conventional rotary connector is disclosed, for example, in Japanese Patent No. 3-55955. This conventional connector includes a rotor housing and a stator housing assembled to each other into a complete housing assembly in which a flat cable in the shape of a spiral is housed and electrically connects the vehicle body and the steering wheel.
The conventional rotary connector is used for an air bag system or an alarm device mounted to the steering wheel. Thus, the current that flows through the connector is small. Accordingly, the flat cable includes thin wires covered with a thin film.
However, the aforementioned conventional rotary connector can be used only for low current applications. Thus, the conventional rotary connector cannot be applied to a heater that heats a steering wheel, because the heater requires a large current. If the heater current flows through a conventional flat cable, the conductors in the flat cable generate heat sufficient to melt the film covering the conductors.
An object of the present invention is to solve the problems associated with the aforementioned conventional rotary connector. More specifically, an object of the invention is to provide a rotary connector suitable for an electric apparatus that is assembled into a steering wheel and consumes a relatively large current.
Additional objects, advantages and novel features of the invention will be set forth in part in the description that follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
The present invention comprises a rotary connector having: a stator housing mounted on a vehicle body of an automobile; a rotor housing rotatably mounted to the stator housing and coupled to a steering wheel; an attachment that couples the rotor housing to the stator housing so that the rotor housing is rotatable relative to the stator housing; and a flat cable accommodated in a space defined by the rotor housing and the stator housing. The attachment has an annular flange formed at an outer periphery thereof, and a slip-ring mechanism provided between the flange and a bottom section of the stator housing.
According to another feature of the invention, the rotary connector has the flat cable and a cord, and the cord has one end thereof connected to a device mounted on the steering wheel and the other end thereof connected to the slip-ring mechanism through a shaft sleeve.
According to another feature of the invention, the flange of the attachment supports movable contact plates of the slip-ring mechanism thereon; and the bottom of the stator housing has a non-movable contact plate thereon on which the movable contact plate slides.
According to another feature of the invention, the movable contact plate is provided on the flange of the attachment and connected to the cord, and the non-movable contact plate is insert-molded in the bottom section of the stator housing.